#include<reg52.h>
#include<intrins.h>
#define uint unsigned int
#define uchar unsigned char
void delayms(uint);
uchar aa;
void main()
{
aa=0xfe;
while(1)
{
	P0=aa;
	delayms(500);
	aa=_crol_(aa,1);
}
}
void delayms(uint xms)
{
uint i,j;
for(i=xms;i>0;i--)
for(j=110;j>0;j--);
}
